I thought about adding another function when you hold down a smartcast assigned button on skillshots.
How about if: whenever you keep holding down a SC button, it will show you skillshot direction arrow (missile path).
We know that the purpose of SC is to immediately cast an attack whenever button is pressed, but this can be sometimes difficult for skillshots, as there will be situations where you'll want for a brief moment to have certainty of direction when champion is moving and aiming.
Of course, you can always reassign another button with the normal functionality, but that means:
1. Invest on another keyboard button, just for the same skill.
2. Normalcast doesn't has the charm of just pressing one button avoiding left clicking thing, you just want to have notion of direction.
Just think of it, similar mechanic when you use victor's laser or Rumble's ult, (of course, vector's origin is on the character, not on the place where your cursor is pointing like Victor & Rumble's case).
This could also apply to other type of skills (i.e. AoE), where you want to be able to see the radial range circle enabled with SC. But actually I thought on just applying this exclusively on Skillshots.
PD: sorry for the tl;dr. Hope that i posted in the correct forum.